Roofing products are generally flat or sheet-like materials that can be arranged on a roof to prevent weather, e.g., wind, water, etc., from entering a roof structure. A roofing product can also serve to reflect heat energy from a roof. The roofing product should be durable enough to perform these functions for a number of years. Examples of roofing products include asphalt-based, wooden, or ceramic tile shingles.
Roofing products, particularly those which employ roofing granules, generally have been prepared from a water-proof, durable substrate having roofing granules disposed on a surface of the substrate. Asphalt-based roofing shingles, for example, typically comprise an asphalt-based substrate with roofing granules embedded into the asphalt. The roofing granules are generally colored to provide a desired aesthetic value upon application of the roofing product onto a building. These types of products are prepared by conventional practices generally recognized in the roofing products industry.
There is a continuing need in the roofing product art for new roofing product constructions, and for new processes for preparing roofing products. Conventional roofing products, such as shingles, are often susceptible to weather related damage that can either tear the base substrate or adversely affect the bond of the granule in the asphalt-based substrate. The release of the granules from the base permits the passing of light through to the asphalt. The light can degrade the asphalt and may cause premature failure of the roofing product.
The asphalt-based substrate can adversely affect the aesthetics of the coated granules applied onto the substrate. For example, lighter colored granules may darken upon application to the asphalt-based substrate. The darkening can be attributed to exposed black asphalt in gaps surrounding the granules. Additionally, the lighter color pigments may darken over time after application onto a roof due to the migration of the lower molecular weight materials from the asphalt onto the surface of the coated granules. The aesthetics of a roofing product can also be effected by the undesirable growth of algae on the exposed surface of the roofing product. Algae, growing on the exposed surface of the granules, may have direct access to the asphalt, which provides nutrients that can sustain growth.
It would be an advantage to provide a roofing product that is capable of withstanding severe weather conditions and capable of preventing the degradation of the underlying asphalt-based substrate. It would also be an advantage to provide a roofing product that prevents the discoloration of granules when applied onto an asphalt-based substrate.